What does it feel like when a spot is rich or lean??

[Darin Jordan]

sorry for the hijack darin

No worries! That's why I'm having this stuggle in "public"! Hopefully someone else can learn from me asking all these dumb questions!

[salty_monk]

I went through something similar with my 1000G. Turned out the Ignitor was toast. Basically you would ride along & then it would hit a wall, no more power, just a constant flat blah... (hard to describe).

Would be one of the things I would check out - a hell of a lot of "carb problems" are electrical...

[Darin Jordan]

I went through something similar with my 1000G. Turned out the Ignitor was toast. Basically you would ride along & then it would hit a wall, no more power, just a constant flat blah... (hard to describe).

Would be one of the things I would check out - a hell of a lot of "carb problems" are electrical...

I think I've read that here before. I'll check it out. Going to be kind of hard to diagnose a faulty/intermittent ignitor though, eh??

Why do I see me having to explain the purchase of a Dyno-S system to my wife in my near future???

[49er]

Well, guys... I put the needles back to the 3rd slot, and installed 170 mains... very little effect! The stumble is still there, and I'm a little frustrated...

HOWEVER, I shall persevere!

I've had every main in there from 155 up to 175, and had needle settings from 2 down from middle, to 2 up from middle, and NONE of this seems to have an overall effect on the severe WOT stumbling I'm getting.

SO, I'm going to go through the entire wiring harness, or at least those parts affecting the ignition, including cleaning up the fuse box, as BassCliff recommends. I'm also going to pick up a relay tonight and do the relay mod for the ignition. I'll test the voltage to the coils, and make sure the plug boots are sufficiently low resistance.

Going to make sure that the ignition system is delivering full spark throughout the RPM range and see if perhaps THAT is the issue.

What I discovered yesterday is that at full WOT, the bike pulls to 5000, and then starts stumbling/cutting out. It actually seems to do this at anything over about 1/2-2/3rds throttle, but is quite obvious at WOT. I DOES rev right up to around 8500 or so in the gears where that is possible to do without opening the throttle up that far, but even then, at some point you have to open it up further and then the stumble starts...

I may end up right back at jetting, but since it seems to happen at exactly the same RPM, regardless of gear or load, I suppose it could be a weak ignition. Time to eliminate that possiblity, anyhow...

Darin, I'm not ruling out electrical issues as others have suggested but to me your symptoms sound like the engine is getting starved of fuel when it is under high demand. Doing a plug chop at that time should reveal a lean condition. If the plugs are sooty then it probably confirms an electrical issue.

Have you checked the fuel flow through your petcock? I'd remove it, clean it and check that the filter in the tank isn't clogged up reducing flow. Also, are you sure that the float levels are correctly set? If they are set too low, you will also experience the problem you have described.

[Darin Jordan]

Have you checked the fuel flow through your petcock? I'd remove it, clean it and check that the filter in the tank isn't clogged up reducing flow. Also, are you sure that the float levels are correctly set? If they are set too low, you will also experience the problem you have described.

The petcock is freshly rebuilt and is operating correctly. Float level was set to the stock settings, but I recently raised it about 1.5mm or to see if that would help. No difference could be felt.

I'll admit, it DOES feel like it's running out of fuel supply, but there seems to be plenty of supply there... I'll double check it again, just to be sure.

Dynojet also mentioned something about the float-bowl breathers needing to have the lines removed and the outlets turned down. I've done that. I've also tried adding lines and routing them to a place with non-turbulent airflow, etc... All to no avail.

I'm left to think that it may be ignition related, so I'll try to rule that out for now. One would think that SOMETHING I've done to the carbs would have made some move towards a difference, better or worse, but thus far, the problem remains. Verifying the ignition system seems prudent at this point.

[49er]

The petcock is freshly rebuilt and is operating correctly. Float level was set to the stock settings, but I recently raised it about 1.5mm or to see if that would help. No difference could be felt.

I'll admit, it DOES feel like it's running out of fuel supply, but there seems to be plenty of supply there... I'll double check it again, just to be sure.

Dynojet also mentioned something about the float-bowl breathers needing to have the lines removed and the outlets turned down. I've done that. I've also tried adding lines and routing them to a place with non-turbulent airflow, etc... All to no avail.

I'm left to think that it may be ignition related, so I'll try to rule that out for now. One would think that SOMETHING I've done to the carbs would have made some move towards a difference, better or worse, but thus far, the problem remains. Verifying the ignition system seems prudent at this point.

After re-reading your earlier post, your plug colour is classic leanness. If it was an electrical issue, I would expect the plugs to have darkened due to partially burnt vapours in the chambers.

Are you running an additional inline fuel filter? These often cause fuel starvation problems.

You can eliminate fuel starvation from the list by shutting off the engine when it starts playing up. Put the bike on the centre stand and remove one of the outer carb drain plugs to see how much fuel runs out. If fuel gushes out, and you collect equivalent to 1/3 to 1/2 a bowl of fuel, you don't have a fuel delivery problem.

[BassCliff]

Hi,

The petcock is freshly rebuilt and is operating correctly. Float level was set to the stock settings, but I recently raised it about 1.5mm or to see if that would help. No difference could be felt.

I'm sure you already know this but I thought I'd mention it.

If you raised the float height while the carbs were upside down, then you have actually lowered the fuel level in the bowls. When you lower the float height (when checking upside down) then the fuel level in the bowls will be higher.




Thank you for your indulgence,

BassCliff

[Darin Jordan]

Are you running an additional inline fuel filter? These often cause fuel starvation problems.

Nope... just a standard 5/16" fuel line.

You can eliminate fuel starvation from the list by shutting off the engine when it starts playing up. Put the bike on the centre stand and remove one of the outer carb drain plugs to see how much fuel runs out. If fuel gushes out, and you collect equivalent to 1/3 to 1/2 a bowl of fuel, you don't have a fuel delivery problem.

So, if fuel is flowing freely through the petcock when I apply vacuum to it, or when I turn it to prime, wouldn't that tell me the same thing?

I guess the most puzzling part is that this is simply a stock GS850G motor... Nothing has been done to it that should have it requiring anything special to make work correctly. I've been trying to follow all the basics on BassCliff's site, and none of it seems to be working. I'll verify that the ignition isn't an issue next.

I wouldn't expect that this motor should require an extra rich set of jets to make work correctly, given the above information. It doesn't have anything special for a cam, or header, or anything else.

Now... I suppose that I could take the needle jet to the extreme and move the clip all the way to the bottom, and see what kind of effect that has. One would expect that to make SOME kind of difference, right?

I did notice that these Dynojet needles are a little bit longer than the stock ones. I've measured the diameter and according to DJ, these are the right size, diameter wise, anyhow. I'm just assuming they kitted the right parts. Maybe I'll try going extreme rich on the needles and see what that effect is. Good or Bad, at least it would be a difference that I could use as a data-point, one would assume.

Thus far, NONE of the jetting adjustments have had ANY appreciable affect on this situation, and, like I mentioned, I've been from 155 all the way up to 175, all to no effect, and moving the needle up or down 2 notches hasn't seemed to make a noticable difference either, or, if it did, it was too subtle for me to pick up on.

[Darin Jordan]

Hi,



I'm sure you already know this but I thought I'd mention it.

If you raised the float height while the carbs were upside down, then you have actually lowered the fuel level in the bowls. When you lower the float height (when checking upside down) then the fuel level in the bowls will be higher.

Cliff,

Thanks, but yes, I did it correctly. I actually made a gauge that I could use while the carbs were in the bike, and I very carefully adjusted each of them (which takes a bit of time when carbs are in the bike, I might add). I've also verified the levels with site-tubes with the carbs mounted. The float levels aren't likely the issue, but then, either should be 10 other things...

[OldVet66]

From personal experience, and this is on VM carbs with 4-1 pipes and pods, I was too rich on the needles. It would start sputtering at around 5500-6000 RPM's, and there was an unwillingness to run smoothly up to red line. low end, idle and normal riding was fine. As it got hotter out it finally told on itself, and started fowling out plugs if I tried to force it through to red line. I dropped the needles back down to DJ's recommendations and everything cleared up. It just goes to show that every motor is a little different and what works for most won't work for all.

[Darin Jordan]

Did some electrical cleanup tonight and got it all back together. Rode about 20-miles, and decided to do a plug chop as I as coming home. This one happens to have been a 1/4 throttle chop, but the plugs look pretty much like they did during the WOT chop.

Am I wrong in thinking that these stlll look too lean? I know they are a little dark around the outside, but I think that's just from the off throttle riding. The insulator and electrode look really dry, and have almost no color.

If it makes a difference, the headers seem to be running around 360-degrees F about 7" out of the head, and the motor head temp was around 240 or so, all of which feels a little warm to me.

Thoughts??

[Darin Jordan]

Here's another plug shot, this time without the supplemental lighting.

For reference...

DJ Stage III
170 mains (DJ recommends 165)
DJ Needles set at recommended 3rd slot from top
Pilot screws at 5-turns out
All new O-rings in carbs, new manifolds, new manifold o-rings

[49er]

Here's another plug shot, this time without the supplemental lighting.

For reference...

DJ Stage III
170 mains (DJ recommends 165)
DJ Needles set at recommended 3rd slot from top
Pilot screws at 5-turns out
All new O-rings in carbs, new manifolds, new manifold o-rings

If that's at 1/4 throttle, your pilot circuit is too rich. There's nothing wrong with your porcelain colour. Mine run lighter colour than that with no heating issues.

Do DJ not suggest changing pilots up one size for pods? It seems crazy to be running the mixture screws so far out (5 turns). That setting is way too rich according to your plug base ring colour. Are you still running B8ES plugs?

[Darin Jordan]

If that's at 1/4 throttle, your pilot circuit is too rich. There's nothing wrong with your porcelain colour. Mine run lighter colour than that with no heating issues.

Do DJ not suggest changing pilots up one size for pods? It seems crazy to be running the mixture screws so far out (5 turns). That setting is way too rich according to your plug base ring colour. Are you still running B8ES plugs?

I've installed the main air correctors that DJ sent with their kit, installed as they recommended. (tap lightly in place with their included tool and put a drop of the included glue). I didn't see anything in there about pilot jets, but I'll go look again.

The pilot screws started at the recommended 4 1/2 turns, and I was still getting the backfiring on decell and a some popping/crackling at very light throttle openings. Everything I've read here suggests that means lean on the Pilot circuit, so I've been opening them, 1/4 turn at a time. I'm open to going the other way if that's not correct. In fact, I'm pulling the tank again shortly and am setup to do the "Highest Idle" deal here this weekend. I don't disagree that it seems to be a bit rich at idle and part throttle... If I'm getting an air leak in the system somewhere, I sure don't know where it would be from... everything is brand new and correctly installed, and all of the cylinders are running in synch and responding the same to adjustments...

I'm suppose to take a long road-trip at the end of the month with this thing... I'd sure like to get this sorted out before then.

SO.... if the plugs look like this after a full-throttle chop, with it stumbling and bumbling so hard that it simply won't accellerate.... what does that mean to me? The million-dollar question!

[Darin Jordan]

7. Engine accelerates until the midrange then pauses, stumbles, or shuts down until you back off the throttle. This problem gets worse the higher the gear used.
• Verify the parameters on the Fact Sheet are being met. For example, the mains are stage 1 mains if you have the stock air box. The stage 3 mains are used with the individual filters.
• Verify the intake and exhaust flow matches those described by Dynojet.
• Verify the float bowl vent tubes are removed (not applicable to Pressurized Air Box Models).
• Verify proper installation of parts, spacers under the needle etc. as Dynojet recommends, and that your needles and mains are all matched and free of obvious defects.
• If these items check out, lower the needle down to fix a slight pause or stumble. Lower the needle and install a smaller main jet to fix a more severe problem.

Almost seems to fit the symptoms... I've had a smaller, 160 main in there... Maybe I need a 155?? I'm grasping now, obviously... I've tried to do the "choose the correct main first" route, but I can't GET into the mains with it stumbling like this at WOT... so how the heck do I do that!?

Hahahaha... you guys DID warn me that Pods were fun! Not ready to turn back just yet...